Water Heater Leaking or Condensation - Rheem Gas 40 Gal Powervent

I have an 11-year old Rheem 40 Gal PowerVent gas hot water heater and it appears as though it is leaking. I've done some initial research on the topic and I think it is time for an expert.

The leak is tiny so far and it is coming from the bottom "pan" area...specifically where each of the three support legs are attached to the water heater shell. I checked the pressure valve (released it and it snapped back...grimy water came out)--that seemed ok. I also checked the plumbing connections on top and they all seem dry as a bone. Last, I opened the service panel and peered into the chamber where the flame is located. Inside, the pan directly underneath the flame is dry, however the sheet metal beneath that and on the bottom is wet (the outside water heater casing). The water is running from the three legs. Since the service hole is small I cannot get a complete look inside the chamber. From what I can see, I do not see any evidence of water leaking from above the flame or at the outside seam. The belly of the tank (inside the combustion chamber) is full of black flecks, like pepper.

Condensation usually happens when there is a heavy water draw or if the incoming cold water is very cold. You can often hear sizzling or pinging sound, when the condensate is dripping on the hot burner.

So my question is... did you hear anything when Rheem water heater is working? If this is what happens, condensation should disappear after water inside the tank is heated.

So, condensation should stop fairly quickly after the tank fires up. If you see water under the water heater all the time, that's a leak.

On the other side the worst thing it can happen is the corrosion, which might occur in your case as the water heater is already over 10 years and you already saw marks at the bottom of the tank.

Did you, during these 11 years, change the anode rod. Anode rod, which protect the water heater from corrosion should be changed as recommended, otherwise you will see early problems with the rust.

If the leak is not from the fittings and connections and there is no condensation, you have to buy a new water heater as the tank leaking cannot be fixed.